A number is divisible by 9, if the sum of the digits is divisible by 9
METHOD
Step 1. Add up the digits of the given number
Step 2. If the sum is divisible by 9, then the number is also divisible by 9.
Example 1. Consider the number 378
Step 1. 3 + 7 + 8 = 18
Step 2. 18 / 9 = 2
Since the sum of the digits is divisible by 9, so 378 is also divisible by 9.
Check. 378 / 9 = 42
Example 2. Consider the number 427
Step 1. 4 + 2 + 7 = 13
Step 2. 13 / 9= 1 remain 4
Since the sum of the digits is not divisible by 9, so 427 is also not divisible by 9.
Check. 427 / 9 = 47 remain 4
Example 3. Consider the number 8253
Step 1. 8 + 2 + 5 + 3 = 18
Step 2. 18 / 9 = 2
Since the sum of the digits is divisible by 9, so 8253 is also divisible by 9.
Check. 8253 / 9 = 917
Example 4. Consider the number 20872
Step 1. 2 + 0 + 8 + 7 + 2 = 19
Step 2. 19 / 9= 2 remain 1
Since the sum of the digits is not divisible by 9, so 20872 is also not divisible by 9.
Check. 20872 / 9 = 2319 remain 1
| Number | Step 1 | Step 2 | Step 2 Divisible by 9? | Number Divisible by 9? |
|---|---|---|---|---|
| 378 | 3 + 7 + 8 = 18 | 18 / 9 = 2 exactly | Yes | Yes |
| 427 | 4 + 2 + 7 = 13 | 13 / 9 = 1 remain 4 | No | No |
| 8253 | 8 + 2 + 5 + 3 = 18 | 18 / 9 = 2 exactly | Yes | Yes |
| 20872 | 2 + 0 + 8 + 7 + 2 = 19 | 19 / 9 = 2 remain 1 | No | No |
